Abstract: A roll-to-roll rapid thermal processing (RTP) tool with multiple chambers for forming a solar cell absorber by reacting a precursor layer on a continuous flexible workpiece. The RTP tool includes an elongated housing having a heating chamber with a predetermined temperature profile, a supply chamber and a receiving chamber. The heating chamber includes a small process gap in which the precursor layer is reacted with a Group VIA material to form an absorber layer. The continuous flexible workpiece is unrolled and advanced from the supply chamber into the heating chamber, and the processed continuous flexible workpiece is taken up and rolled in the receiving chamber.

Abstract: An evaporation tool for forming a dopant structure on a front surface of a continuous workpiece, wherein the front surface includes a precursor layer to form Group IBIIIAVIA absorbers for solar cells and the dopant structure is used to introduce dopants into the precursor layer. The tool includes at least a first vapor source station to deposit a Group VIA material, such as Se, and a second vapor station to deposit a dopant material, such as Na, onto the continuous workpiece. A moving assembly of the tool holds and moves the continuous workpiece within the tool by feeding the continuous workpiece from a first end and taking up from a second end of the tool. A support assembly of the tool contacts a back surface of the continuous workpiece to remove the heat from and apply tension to the continuous workpiece during the process.

Abstract: The present invention provides for new ohmic contact materials and diffusion barriers for Group IBIIIAVIA based solar cell structures, which eliminate two way diffusion while preserving the efficient ohmic contacts between the substrate and the absorber layers.